Equis ISSN 2398-2977

Abdomen: ventral midline hernioplasty

Contributor(s): Graham Munroe, Jarred Williams

Introduction

  • A hernia can be defined as a protrusion of an organ through the wall of a cavity which normally contains that organ.
  • An abdominal hernia is where one or more abdominal organ protrudes to some degree through a congenital or acquired opening in the abdominal wall.
  • Congenital hernias are present at birth. The most common of these are umbilical hernias and their diagnosis and treatment is covered elsewhere Umbilicus: hernia.
  • Acquired hernias of the abdomen most commonly occur in the midline following breakdown of a ventral midline laparotomy. Lateral abdominal hernias are usually post trauma such as kicks, falls, or collisions with fences, vehicles or other solid objects.
  • Complete breakdown of all of the layers of a ventral midline laparotomy (celiotomy) Abdomen: laparotomy leads to eventration of the abdominal contents. Total dehiscence of the abdominal wound either occurs acutely during recovery from the anesthesia for the abdominal surgery or as a delayed post-operative complication.
  • Partial breakdown of only the repaired linea alba occurs post-operatively as a complication of healing of the celiotomy. This is the most common cause of a ventral midline incisional hernia Abdomen: hernia - incisional.
  • The incidence of ventral midline herniation ranges from 8.1-16% in various studies. Risk factors include post-operative drainage and/or sepsis of the surgical wound, poor surgical technique during the celiotomy, and repeat celiotomy.
  • Midline incisional hernias often do not appear immediately and commonly are identified several months after the surgery.
  • Not all incisional ventral midline hernias require surgical repair. Usually it is repaired either for cosmetic reasons or where the animal is to undertake athletic work or breeding (pregnancy).
  • Incarceration within the hernia is rare.

Uses

Advantages

  • Returns the abdominal wall to normal strength.
  • Improves the cosmetic appearance.

Disadvantages

Requirements

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Preparation

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Procedure

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Aftercare

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Outcomes

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Prognosis

  • Primary closure without the use of a prosthetic mesh:
    • Used successfully to repair hernias up to 28 cm long or 18 cm wide.
    • Short-term complications in 4 of 38 horses undergoing this repair and included partial failure of the repair.
    • Long-term complications were only 4 %.
  • Prosthetic mesh onlay with primary closure:
    • Results of this technique vary in the literature with one author describing good results and minimal complications in over 75 horses where this technique was used. In another study, a high incidence of complications was reported (4 of 9 cases), including colic and implant infection (post-discharge from hospital).
    • Two of the horses required subsequent implant removal to resolve the infection.
    • This technique has the advantage of simplicity, limited dissection and good cosmesis. Rarely does the mesh become infected and it is easily removed if it does.
  • Prosthetic mesh inlay (interposition):
    • This technique is not popular in human medicine because of high recurrence levels of the hernia post repair.
    • It is rarely used in horses, but one report discussed its use in 3 cases of incisional hernia after ventral midline celiotomy.
    • All 3 cases experienced no complications.
  • Prosthetic mesh sublay with primary closure or with fascial overlay:
    • A retrospective study of incisional hernia repair in 13 horses (> 450 kg bodyweight) which underwent preperitoneal sublay mesh implantation revealed that all the horses exhibited signs of mild to moderate abdominal pain Abdomen: pain - adult in the first 24 h post-operatively.
    • Seroma/hematoma Hematoma formation at the site of surgery was present in all cases, with 8 developing incisional drainage.
    • All complications were managed in all but one of the cases by local and/or systemic antimicrobial drugs Therapeutics: antimicrobials, and drainage of the seroma/hematoma by stab incisions.
    • Three horses had disruption of the internal abdominal oblique muscle near the mesh-tissue interface leading to a painful swelling.
    • Long-term follow-up revealed 6 of 12 horses were euthanized post-operatively for recurrent abdominal pain Abdomen: pain - adult (4), laminitis (1) or hernia recurrence (1) post parturition.
    • A better outcome was reported in another study of 15 horses where incisional hernias were repaired using preperitoneal sublay of a folded polypropylene mesh.
    • Complication over a 6 month period in the 14 surviving cases included recurrent colic (1), failure in the repair after a fall (1), abscess formation which resolved with drainage (1), and moderate-severe incisional edema which resolved with time (3).
    • One horse was euthanized due to an unrelated problem.
    • Recently, a preperitoneal sublay placement of a novel absorbable silk mesh was reported in a 600 kg horse with good results.
  • Laparoscopic repair with intraperitoneal mesh underlay:
    • Post-operative complications noted in 5 horses that underwent this surgery, included signs of parietal pain when the site of the repair was palpated at 24-72 h after surgery (5), and drainage from one of the stab incisions which required 5 days of antimicrobial treatment Therapeutics: antimicrobials to resolve (1).
    • All 5 horses had a good functional and cosmetic outcome.

Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Whitfield-Cargile C M et al (2011) Comparison of primary closure of incisional hernias in horses with and without the use of prosthetic mesh support. Equine Vet J Suppl (39), 69-75 PubMed.
  • Caron J P & Mehler S J (2009) Laparoscopic mesh incisional hernioplasty in five horses. Vet Surg 38 (3), 318-325 PubMed.
  • Kelmer G & Schumacher J (2008) Repair of abdominal wall hernias in horses using primary closure and subcutaneous implantation of mesh. Vet Rec 163 (23), 677-679 PubMed.
  • Freeman D E (2005) Management of ventral incisional hernias in large horses: a surgical challenge. Equine Vet Educ 17, 247-251 WileyOnline.

Other sources of information

  • Toth F & Schumacher J (2018) Abdominal Hernias. In: Equine Surgery. 5th edn. Eds: Auer J A & Stick J A. Elsevier Saunders, USA.


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